Bottom flap trimmer with adjustable fixed blade



Jan. 26, 1965 K. STEMMLER BOTTOM FLAP TRIMMER WITH ADJUSTABLE FIXED BLADE 2 Sheets-Sheet 1 Filed Sept. 20, 1961 Jan. 26, 1965 K. STEMMLER 3,156,965

BOTTOM FLAP TRIMMER WITH ADJUSTABLE FIXED BLADE Filed Sept. 20. 1961 2 Shee ts-Sheet 2 U ted statfis signments, toWinkler, & Donnebier Maschinenfabrik und Eisengiesserei, Neuwied am Rhine, Germany, a konimanditgesellschaft of Germany Filed Sept. 20, 1961, Sci. No. 139,453 5 Claims. (Cl. 83-175) This invention relates me high speed trimmer or cutter for paper and the like, and more particularly is concerned with mechanisms for cutting or trimming moving webs of articles of paper between a rapidly rotating knife blade and a stationary cutting edge. Although the invention will be described and illustrated in a bottom flap trimmer for web-cut paper envelope blanks, obviously the concepts involved apply to paper cutters or trimmers of different configurations .and useful for many other purposes.

In modern high speed paper trimmers of the character here discussed, the paper cutting elements are required to operate many times per second, and if the cutting is to produce uniformly clean edges the positions of the elements must be precisely adjusted to close working tolerances and they must be maintained at all times in proper relation with respect to each other. Unfortunately, the high speed of operation of the machine after a time causes the cooperating cutting elements to heat upbecause of friction. The heated parts naturally expand and throw the cutting edges out of their desired precisely adjus't'ed positions. This introduces undesirable wear on the cooperating parts or produces imperfect cuts in the paper for obvious reasons. Readjustment or replacement of thescutting elements will then be necessary, usually requiring that the machine be shut down, the parts readjusted or replaced, and the machine again started. True, the cuttingielements might be adjusted before starting so that expected thermal expansion would be compensated for in advance, but in that case the warm-up period of the machine is lengthened, imperfect cuts are made at the beginning, of a run while the parts are becoming heated, and the optimum adjustment is never made excepting by lucky accident or by a skilled operator having long experience with a particular machine and its characteristics. Artificial heating of the cutting elements. in advance of. operation has been suggested, but this imposed heating can never be of the same exact degree and extent as the natural operating heating of the parts, and shutdowns for final precise adjustment may still be necessary.

An object of the present invention therefore is to provide, in a high speed paper cutter with a stationary edge opposite a rotating knife, means to adjust the stationary edge readily and precisely with respect to the knife while the machine is running at highspeed. In this Way production may be maintained even While the machine is warming up and the cutter need not be stopped to make desired adjustments.

An additional object is to provide a mounting for stabilizing the stationary edge of a paper cutter (luring operationso that desired positions of adjustment will be maintained unless deliberately changed.

A further object is to provide configurations, positions and materialsfor the cooperating parts in a high speed paper cutter such that wear will be minimized, jamming will be prevented and replacement of worn or damaged parts will be required less frequently. Still further, the invention provides means for quickly removing and replacing parts in a paper cutter so that when this is requiredit maybe done with a minimum of lost time.

Another object is to provide simple and reliable means to dispose of trimmings or chips in a paper trimmer so that such chips will not interfere with subsequent operations of the trimmer. v

Still another object is to provide improved means for transporting and positioning articles of paper in a paper trimmer so that the machine will producetrimmed articles in a reliably uniform fashion.

These and incidental objects and advantages are obtained in this inventionby pivotally mounting the stationary edge of a cutter about a rotating shaft which also carries driving rolls for transporting the paper past the cutter. An adjustment arm eir tendingfrom the pivoted element which carriesrthe stationary edge islarr'anged to be precisely positioned and held from a fixed location on the machine which does not interfere with the paper feeding and cutting mechanisms. The cooperating rotating knife is carried by another driven paper transporting roll which serves the further functions of holding the paper in proper relation to the stationary edge while feeding the paper andof imposing a slight stretch on the paper for improved cutting action. Thestationary edge is soformed and positioned with respect to the rotating'knife that there is little wear or likelihood of jamming between the parts in all positions of adjustment, and the material chosen for the stationary edge is calculated further to resist Wear Which might require frequent replacement.

Other objects and further details of that which is believed to be novel and included in this invention will be clear from the following description and claims, taken with the accompanying drawings in which is illustrated an example of a bottom'fiap trimmer for envelopes embodying the present invention and incorporating the pivotally mounted adjustable stationary cutting edge and other features outlined above.

In the drawings:

FIG. 1 is an end or elevational view of a bottom flap trimmer according to this invention, certain parts being shown in section for clarity, and other parts of an entire machine being indicated only to the extent necessary to understand the construction and operation of the paper cutting elements;

. FIG. 2 is a vertical side sectional view of. the trimmer shown in FIG. 1, taken on the line 2-'-2 of FIG. 1, and

FIG. 3 is a greatly enlarged side or edge view of the tips of the adjustable stationary cutting edge and of the cooperating rotating knife of this machine, showing the configurations of these parts and their preferred positions with respect to each other during the paper cutting operation.

The exemplary paper cutter is included as part of a machine which receives and feeds diamond shaped envelope blanks previously produced from a web of paper. One obtuse corner of each diamond blank will be cut off and this portion of the blank will ultimately become the bottom flap of the envelope after the edges of the diamond have been notched and the blank has been folded. Because the cutter shown here trims off the obtuse corner on the diamond blank it therefore is called a bottom flap trimmer.

Before reaching the trimmer the diamond shaped blank is fed horizontally on any acceptable or conventional transporting means along a paper line 5, toward the trimmer in the direction shown as from right to left in FIG. 2. The trimmer requires two rotating shafts an upper shaft 6 and a lower shaft 7, both driven at the same speed from appropriategears or otherjdriving arrangements, the upper shaft 6 rotating in a clockwise direction, the lower shaft rotating counterclockwise as seen in FIG. 2.

The lower of these driven shafts carries a pair of opposed, spaced cup-shaped lower transport rollers 8, suitably secured to the shaft as by set screws 9. Cooperating resses c.) with these lower transport rollers are a pair of smaller upper transport rollers 11 which function in the manner of idlers and do not drive by themselves. The paper line passes between the rollers 8 and idlers iii.

In the center of this part of the machine, in the space 12 between the open ends of the opposed cup shaped rollers ii, the stationary lower edge 13 is mounted. The tip 14 of this edge is made of a tough material such as carbide and it is deliberately rounded as shown rather than being brought to a sharp cutting angle or edge.

The edge 13 with its cutting tip 14 is made to be readily adjustable and replaceable, being fixed to the end of a mounting block or plate 15 removably and adjustably secured as by machine screws 16 to the adjustable stationary edge holder 17. The holder 17 may be extended as at 18 at its ends into the lower transport rollers and is pivotally mounted with respect to these rolls and the lower shaft 7 which carries them, being held in proper spaced and pivotal relation with respect to these parts as by anti-friction bearings 19 extending between the holder and the shaft '7 on which it is pivotally mounted. The pivotal action between the holder and the shaft provides for fine accurate adjustment of the tip 14 as will be later described, and the securing of the holder in any of its pivotal adjusted positions may be accomplished in any suitable fashion. For example, an adjustment arm 2?. may be bolted or otherwise firmly secured to the holder 17 in the space between the rollers and generally 0-pposite the edge 13. The arm 21 is extended in a generally radial direction with respect to the axis of the shaft on which the holder is pivoted, and the free end of the adjustment arm placed between opposite sides of an adjustment yoke 22 fixed at a readily accessible location on the body, frame or base 23 of the machine remote from the cutting elements. Opposed adjustable set screws 24 threaded into the sides of the yoke 22, or equivalent adjustment means, may be used in a manner readily understood to move and hold the free end of the adjustment arm 21 toward one or the other of the sides of the yoke, tilting the holder 17 about the axis of its mounting shaft '7 so that the tip ll l will be correspondingly adjusted in an arcuate path just outside the circumference of the rollers 8. As shown, because the free end of the radial arm 21 is much further away from the axis of the shaft '7 than is the tip 14, incrementsof movement of the arm 21 will result in correspondingly smaller movements of the tip 14. In a machine according to the invention it has been found that adjustment of the tip 14 over an arc spanning less than 10 is satisfactory.

A cutter as described has remarkable stability while the machine is operating at high speed. It is theorized that this may be due to a gyroscopic effect of the rapidly along the paper line 5 it is caught between the driven lower transport rollers S and the idling transport rollers lll. It is fedtherebetween until the leading obtuse corner of a diamond shaped blank is properly overthe tip 1% of the stationary cutting edge 13. At that point in the feed and at a proper time determined by known means which are not part of this invention, the upper rotating shaft 5 will have rotated an upper cylindrical knife holder 25 so that an adjustable knife blade 26 thereon will wipe across the rounded tip 14 of the stationary lower cutting edge and trim a triangular piece or chip from the corner of the blank. The knife blade, unlike the stationary edge with which it cooperates, is provided with a sharp, acute angular tip 27. The tip 14 and the tip 27 must never come into full physical contact with each other because this would damage or destroy these cutting parts. How- 7 ever, they must be positioned so that they come microa tension on the paper which will assist in the cutting action.

For purposes of ready repair and replacement, the knife blade 26 may be, and preferably is, removably and adjustably mounted in the knife holder 25 as by a segmental biock 28 held in place on the knife holder 25 by screws indicated at 29 and carrying recessed head set screws 31 whose inner ends may be tightened against one side of the knife blade 26.

The triangular pieces or chips which are trimmed from the end of the envelope blanks must be disposed of in some fashion, although the remaining part of the blank continues to be fed by any suitably known means along the paper line 5 and away from the cutter. The arrangement for disposing of the chips is built largely within the knife holding cylinder 25 and the shaft 6 which carries it, and consists in providing the segmental knife holding block 23 with a suction opening 32 therein which is connected by suction passageways, 33 in the block 28 and 3d and 35 in the roll 25, leading to a hollow core 36 in the shaft 6. Suction is supplied to the hollow core and thence to the suction opening 32 periodically as the knife holder 25 rotates. This may be done through a stationary valve 37 surrounding the shaft 6 and leading to a constant suction line 38. The shaft 6 is provided with a side opening 39 leading to the hollow core and cooperating with an opening 41 in the valve. Each time the shaft rotates and the side opening 39 comes opposite the opening 41 in the valve, the desired suction will be produced.

in this way, suction is provided at theopening 32 on the rotating knife holder in advance of the location where the cut is to be made, but very close to the cutting edge of the knife. Therefore when a chip is trimmed from the blank it is caught and held immediately by the opening 32 on the knife holder and carried upwardly away from the rest of the blank on the paper line. The cooperating openings 39 and 4-1 are designed to remain in registry with each other to hold the chip on the roll 25 bysuction until the chip reaches an exhaust hood 4-2 which is suit-. ably connected to a system which will carry off the chip by air flow. Obviously, when the chip is under the ex haust hood, the openings 39 and 41 will no longer be in registry and suction will no longer hold the chip on the cylinder 25. Continued rotation of the member 25 will reintroduce the active suction opening 32 in advance of the cutting blade so that the chip from the next envelope to be trimmed may be carried away as before.

It should be noted that the closest possible theoretical approach of the rotating knife edge and the pivotally adjustable stationary edge is in a center line extending between the axis of rotation of the knife and the pivotal axis of the adjustable holder 17. Naturally, as the stationary edge is adjusted away from this center line, the arc of its movement will pull the tip 14 away from 'sidering that the two arcs are very nearly tangent.

edge to the stationary edge is offset from this center line between and M; of an inch in the direction of rotation of the knife. Further arcuate adjustment of the stationary edge is made away from that point, but not below the level of the paper line. As will be clear from an inspection of FIG. 3, the cutting action will therefore take place while the rotating knife tip is moving away from the stationary edge. lammingof the cutting elements is thus prevented. The radius of the tip 14 provides a solid backing and yet a definite line for cooperations of these parts may be designed to produce notches,

diagonal cuts, window openings or other non-linear or slanted trimming or cutting. Also, although individual blanks or articles of paper are operated upon by the exemplary trimmer, it is obvious that the invention may be used for the repeated cutting or trimming of continuous webs of paper.

In addition to the fine adjustment of the cutter, which is obtained through movement of the arm 21 while the machine is running, it should be obvious that both the edge mounting plate and the knife blade 26 may be removed, replaced or roughly adjusted when the machine is stopped, without removing the edge holder 17 or the knife holder 25 from the shafts 6 and i on which they are mounted. This facilitates efiicient servicing of the machine.

As will be clear from the foregoing, certain aspects of the invention are not limited to the precise details here set forth, and it is foreseen that various and other modifications and applications of the invention may occur to those with knowledge and experience in the field of paper cutters and trimmers. It is therefore intended that the following claims shall cover such variations, modifications and applications as do not depart from the true spirit and scope of the invention.

What is claimed as new and is desired to be secured by Letters Patent of the United States is:

1. in a pa er cutter, a rotary knife, a rotating driven shaft, a stationary member p-ivotally mounted on said rotating shaft with a cutting edge positioned adjacent and opposite the arc of rotation of said knife for cooperation therewith in cutting paper fed therebetween, and means for adjusting said cutting edge about the rotating shaft pivot of said stationary member in an arc substantiaily outwardly tangent to said are of rotation of said knife.

2. In a paper cutter, a rotatably driven shaft, a transport roll mounted on said shaft, a stationary adjustabie t5 edge pivoted on said shaft adjacent the roll, means adjusting the angular position of the edge around the axis of the shaft while the roll is rotating, and a rotatable knife with a biade edge traveling in an are adjacent the adjustable edge for paper cutting cooperation therewith.

3. In a paper cutter, a rotatably driven shaft, a pair of transport rolls mounted on said shaft, a stationary adjustable edge pivoted on said shaft between the rolls, means adjusting the angular position of the edge around the axis of the shaft while the rolls are rotating, another transport roll opposing said first named pair of rolls, and a knife carried by said last named roll, rotatably traveling adjacent the adjustable edge for paper cutting cooperation therewith.

4. in a paper cutter, an upper rotary driven member carrying a projecting knife blade tip, a lower pivoted stationary member with a cutting edge adjacent the are of rotation of said blade tip for cooperation therewith in cutting paper fed therebetween, means for adjusting said cutting edge about the pivot of said stationary memher, said pivot comprising a lower rotating shaft, and a pair of lower rotary driven paper transporting rollers on said shaft, one on either side of said pivoted stationary member and rotatable with the shaft.

5. The combination as claimed in claim 4 in which the upper rotary driven member is a roll, and the pair of lower rotary driven paper transporting .rollers and the said upper roll are adapted to engage paper fed therebetween, said upper roll having a greater peripheral velocity than said lower rolis whereby paper therebetween is tensioned against said cutting edge.

References Cited in the file of this patent UNITED STATES PATENTS 1,515,377 White Nov. 11, 1924 1,631,879 Molins June 7, 1927 1,660,950 Zimniewicz Feb. 28, 1928 2,383,523 Thornburgh Aug. 28, 1945 2,429,945 Rayburn Oct. 28, 1947 2,445,831 Hoffman July 27, 1948 2,682,996 Forman July 6, 1954 2,768,689 Ewing Oct. 30, 1956 2,961,909 Hernker Nov. 29, 1960 3,028,742 Hacker et a1. Apr. 10, 1962 3,031,905 Phillips et a1. May 1, 1962 

1. IN A PAPER CUTTER, A ROTARY KNIFE, A ROTATING DRIVEN SHAFT, A STATIONARY MEMBER PIVOTALLY MOUNTED ON SAID ROTATING SHAFT WITH A CUTTING EDGE POSITIONED ADJACENT AND OPPOSITE THE ARC OF ROTATION OF SAID KNIFE FOR COOPERATION THEREWITH IN CUTTING PAPER FED THEREBETWEEN, AND MEANS FOR ADJUSTING SAID CUTTING EDGE ABOUT THE ROTATING SHAFT PIVOT OF SAID STATIONARY MEMBER IN AN ARC SUBSTANTIALLY OUTWARDLY TANGENT TO SAID ARC ROTATION OF SAID KNIFE. 